R-T-B-BASED PERMANENT MAGNET MATERIAL, PREPARATION METHOD THEREFOR AND USE THEREOF

Abstract

Disclosed are an R-T-B-based permanent magnet material, a preparation method therefor and the use thereof. The R-T-B-based permanent magnet material comprises R, B, M, Fe, Co, X and inevitable impurities, wherein: (1) R is a rare earth element, and the R includes at least Nd and RH, M being one or more of Ti, Zr and Nb, and X including Cu, “Al and/or Ga”; and (2) in percentage by weight, R: 30.5-32.0 wt%, B: 0.95-0.99 wt%, M: 0.3-0.6 wt%, X: 0.8-1.8 wt%, and Cu: 0.35-0.50 wt%, and the balance is Fe, Co and inevitable impurities. According to the present invention, under the condition of 0.3-0.6 wt% of a high melting point metal, a permanent magnet material with an excellent magnet performance and a good squareness is obtained.

Claims

1. An R-T-B-based permanent magnet material, which comprises R, B, M, Fe, Co, X and unavoidable impurities, wherein: (1) R is rare earth element and comprises at least Nd and RH; M is one or more of Ti, Zr and Nb; X comprises (a) Cu and Ga, or (b) Cu, Al and Ga; (2) in the R-T-B-based permanent magnet material, by mass percentage: R: 30.5-32.0 wt%; B: 0.95-0.99 wt%; M: 0.3-0.6 wt%; X: 0.8-1.8 wt%, and Cu: 0.35-0.50 wt%; the balance being Fe, Co and unavoidable impurities.

2. (canceled)

3. The R-T-B permanent magnet material according to claim 11 , wherein, the R-T-B-based permanent magnet material comprises R.sub.aM.sub.bX.sub.cT.sub.d phase, wherein, T is Fe and Co, 15 at% < a < 25 at%, 2.8 at% < b < 4.1 at%, 3.0 at% < c < 6.0 at%, 68 at% < d < 78 at%, and at% refers to atoms percentage in the R.sub.aM.sub.bX.sub.cT.sub.d phase.

4. A raw material composition of the R-T-B-based permanent magnet material, which comprises R, B, M, Fe, Co, X and unavoidable impurities, wherein: (1) R is rare earth element, and R comprises at least Nd and RH; M is one or more of Ti, Zr and Nb; X comprises (a) Cu and Ga, or (b) Cu, Al and Ga; (2) in the raw material composition of the R-T-B-based permanent magnet material, by mass percentage: R: 30.5-32.0 wt%; B: 0.95-0.99 wt%; M: 0.3-0.6 wt%; X: 0.8-1.8 wt%, and Cu: 0.35-0.50 wt%; the balance being Fe, Co and unavoidable impurities.

5. (canceled)

6. The raw material composition of the R-T-B permanent magnet material according to claim 4, wherein, X comprises: Cu: 0.35-0.5 wt%, Al: 0.3-0.8 wt%, Ga: 0.2-0.5 wt%; and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material .

7. A preparation method for the R-T-B-based permanent magnet material, wherein, the preparation method comprises the following steps: the molten liquid of the raw material composition of the R-T-B-based permanent magnet material according to claim 4 is subjected to casting, crushing, pulverizing, forming, sintering and grain boundary diffusion treatment, and the R-T-B-based permanent magnet material is obtained.

8. The preparation method for the R-T-B-based permanent magnet material according to claim 7, wherein, the molten liquid of the raw material composition of the R-T-B-based permanent magnet material is prepared by the following method: smelting in a high-frequency vacuum induction smelting furnace; and, the process of the casting is carried out according to the following steps: in an Ar gas atmosphere, cooling at a rate of 10.sup.2°C/sec - 10.sup.4°C/sec; and, the process of the crushing is carried out according to the following steps: hydrogen absorption, dehydrogenation and cooling treatment; pulverizing is jet milling and, the process of the forming is a magnetic field forming method or a hot pressing and heat deforming method; and, the process of the sintering is carried out according to the following steps: preheating, sintering and cooling in vacuum conditions; and, the grain boundary diffusion treatment is carried out according to the following steps: a substance containing Tb or Dy is adhered to the surface of the R-T-B-based permanent magnet material by vaporizing, coating or sputtering, and diffusion heat treatment is carried out; and, after the grain boundary diffusion treatment, a heat treatment is also carried out.

9. An R-T-B-based permanent magnet material prepared by the preparation method of the R-T-B-based permanent magnet material according to claim 7.

10. A use of the R-T-B permanent magnet material according to claim 1 as an electronic component in a motor.

11. The R-T-B permanent magnet material according to claim 1, wherein, X comprises Cu, Al and Ga.

12. The R-T-B permanent magnet material according to claim 1, wherein, R also comprises Pr; or, RH is selected from the group consisting of Dy and Tb.

13. The R-T-B permanent magnet material according to claim 1, wherein, the content of Cu is 0.4-0.5 wt%, and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material; or, when X comprises Al, the content of Al is 0.3-0.8 wt%, and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material; or, when X comprises Ga, the content of Ga is 0.2-0.5 wt%, and the percentage refers to mass percentage in the R-T-B raw material composition of the based permanent magnet material.

14. The R-T-B permanent magnet material according to claim 1, wherein, M is Ti, Zr, Nb or “Ti and Zr”.

15. The R-T-B permanent magnet material according to claim 1, wherein, when M comprises Ti, the content of Ti is 0.3-0.6 wt%, and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material; or, when M comprises Zr, the content of Zr is 0.3-0.6 wt%, and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material; or, when M comprises Nb, the content of Nb is 0.35-0.55 wt%, and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material; or, when M comprises “Ti and Zr”, the content of Ti is 0.2wt% and the content of Zr is 0.3 wt%, and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material.

16. The R-T-B permanent magnet material according to claim 1, wherein, X comprises: Cu: 0.35-0.5 wt%, Al: 0.3-0.8 wt%, Ga: 0.2-0.5 wt%, and the percentage refers to mass percentage in the R-T-B-based permanent magnet material.

17. The R-T-B permanent magnet material according to claim 1, wherein, the R-T-B-based permanent magnet material comprises the following components: R: 30.5-32.0 wt%; B: 0.95-0.99 wt%; Ti: 0.3-0.6 wt%, or Zr: 0.3-0.6 wt%, or Nb: 0.35-0.55wt%; Cu: 0.35-0.50 wt%; Al: 0.3-0.8 wt%; Ga: 0.2-0.5 wt%; Co: 0.8-2.0 wt%; the balance being Fe, and the percentage refers to mass percentage in the R-T-B-based permanent magnet material; or, the R-T-B-based permanent magnet material comprises the following components: Nd: 29.5-31.0 wt%; RH: 0.5-2.0 wt%; B: 0.95-0.99 wt%; Ti: 0.3-0.6 wt%, or Zr: 0.3-0.6 wt%, or Nb: 0.35-0.55 wt%; Cu: 0.35-0.50 wt%; Al: 0.3-0.8 wt%; Ga: 0.2-0.5 wt%; Co: 0.8-2.0 wt%; the balance being Fe, and the percentage refers to mass percentage in the R-T-B-based permanent magnet material.

18. The raw material composition of the R-T-B permanent magnet material according to claim 4, wherein, X comprises Cu, Al and Ga.

19. The raw material composition of the R-T-B permanent magnet material according to claim 4, wherein, R also comprises Pr; or, RH is selected from the group consisting of Dy and Tb.

20. The raw material composition of the R-T-B permanent magnet material according to claim 4, wherein, RH is introduced during smelting and grain boundary diffusion; wherein, the content of RH introduced during the smelting is 0.1-1.0 wt%; the content of RH introduced during the grain boundary diffusion is 0.1-1.0 wt%; and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material.

21. The raw material composition of the R-T-B permanent magnet material according to claim 4, wherein, M is Ti, Zr, Nb or “Ti and Zr”.

22. The raw material composition of the R-T-B permanent magnet material according to claim 4, wherein, the R-T-B-based permanent magnet material comprises the following components: R: 30.5-32.0 wt%; B: 0.95-0.99 wt%; Ti: 0.3-0.6 wt%, or Zr: 0.3-0.6 wt%, or Nb: 0.35-0.55 wt%; Cu: 0.35-0.50 wt%; Al: 0.3-0.8 wt%; Ga: 0.2-0.5 wt%; Co: 0.8-2.0 wt%; the balance being Fe; and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material; or, the R-T-B-based permanent magnet material comprises the following components: Nd: 29.5-31.0 wt%; RH: 0.5-2.0 wt%; B: 0.95-0.99 wt%; Ti: 0.3-0.6 wt%, or Zr: 0.3-0.6 wt%, or Nb: 0.35-0.55 wt%; Cu: 0.35-0.50 wt%; Al: 0.3-0.8 wt%; Ga: 0.2-0.5 wt%; Co: 0.8-2.0 wt%; the balance being Fe; and the percentage refers to mass percentage in the raw material composition of the R-T-B-based permanent magnet material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0148] Fig. 1 shows the distribution of Nd, Ti, Ga and Cu formed by FE-EPMA plane scanning of the sintered magnet prepared in Example 1, where R.sub.aM.sub.bX.sub.cT.sub.d phase is marked with the arrow.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0149] The following examples further illustrate the present invention, but the present invention is not limited thereto. Experiment methods in which specific conditions are not indicated in the following embodiments are selected according to conventional methods and conditions, or according to the product specification.

[0150] The formulations of the R-T-B-based sintered magnet in examples and comparative examples are shown in Table 1.

TABLE-US-00003 No. wt% R Nd PrN d Tb (smel ting) Dy (sme lting ) Tb (diffu sion) Dy (diffu sion) X Al Cu Ga Co B Ti Zr Nb Fe Example 1 30.9 30.2 / / 0.2 / 0.5 1.27 0.6 0.42 0.25 1.0 0.96 0.4 / / 65.47 Example 2 30.5 29.9 / / 0.1 0.5 / 0.85 0.3 0.35 0.2 1.0 0.95 0.3 / / 66.4 Example 3 31.0 30.3 / / 0.2 0.5 / 1.0 0.4 0.4 0.2 0.8 0.97 0.45 / / 65.78 Example 4 31.5 30.0 / / 1.0 / 0.5 1.4 0.6 0.45 0.35 1.2 0.98 0.5 / / 64.42 Example 5 32.0 30.8 / / 0.7 / 0.5 1.8 0.8 0.5 0.5 1.5 0.99 0.55 / / 63.16 Example 6 30.9 / 30.2 0 0.2 0.5 / 1.37 0.7 0.42 0.25 2.0 0.97 0.6 / / 64.16 Example 7 30.9 30.2 / / 0.2 / 0.5 1.27 0.6 0.42 0.25 1.0 0.96 0.2 0.3 / 65.37 Example 8 30.5 29.9 / / 0.1 / 0.5 0.85 0.3 0.35 0.2 1.0 0.95 / 0.4 / 66.3 Example 9 30.5 29.9 / / 0.1 / 0.5 0.85 0.3 0.35 0.2 1.0 0.95 / 0.6 / 66.1 Example 10 31.0 30.2 / / 0.3 / 0.5 1.0 0.4 0.4 0.2 0.8 0.97 / / 0.35 65.88 Example 11 31.0 30.2 / / 0.3 / 0.5 1.0 0.4 0.4 0.2 0.8 0.97 / / 0.55 65.68 Comparativ e Example 1 30.5 29.9 / / 0.1 / 0.5 0.85 0.3 0.35 0.2 1.0 0.95 0 / / 66.7 Comparativ e Example 2 30.5 29.9 / / 0.1 / 0.5 0.85 0.3 0.35 0.2 1.0 0.95 0.7 / / 66.0 Comparativ e Example 3 31.5 30.5 / / 0.5 / 0.5 1.1 0.6 0.25 0.25 1.2 0.98 0.4 / / 64.82 Comparativ e Example 4 31.5 30.5 / / 0.5 / 0.5 0.7 0.2 0.35 0.15 1.2 0.98 0.4 / / 65.22 Comparativ e Example 5 31.5 30.5 / / 0.5 / 0.5 1.45 0.6 0.6 0.25 1.2 0.98 0.4 / / 64.47 Comparativ e Example 6 31.5 30.5 / / 0.5 / 0.5 0.95 0.5 0.2 0.25 1.2 0.98 0.4 / / 64.97 Comparativ e Example 7 30.9 30.2 / / 0.2 / 0.5 1.27 0.6 0.42 0.25 1.0 0.94 0.4 / / 65.49 Comparativ e Example 8 30.9 30.2 / / 0.2 / 0.5 1.27 0.6 0.42 0.25 1.0 1.02 0.4 / / 65.41 Comparativ e Example 9 30.0 29.0 / / 0.5 / 0.5 1.25 0.6 0.4 0.25 1.2 0.98 0.5 / / 66.07 Comparativ e Example 10 32.5 31.5 / / 0.5 / 0.5 1.25 0.6 0.4 0.25 1.2 0.98 0.5 / / 63.57

[0151] Note: Pr: Nd=25:75 (mass ratio) in PrNd; smelting refers to introducting in process step (1), diffusion refers to introducting in process step (8); X refers to the sum of content of Cu, Al and Ga; and “/” indicates that the element is not added.

[0152] The R-T-B-based sintered magnets were prepared as follows: [0154] (1) Smelting process: according to the formulations shown in Table 1, the prepared raw materials were put into a crucible made of alumina and vacuum smelted in a high-frequency vacuum induction smelting furnace and in a vacuum of 5x10.sup.-2 Pa at a temperature of 1500° C. or less.

[0153] (2) Casting process: after vacuum smelting, the smelting furnace was fed with Ar gas to make the air pressure reach 55,000.00 Pa and then casting was carried out, and the quenching alloy was obtained at the cooling rate of 10.sup.2°C/sec - 10.sup.4°C/sec.

[0154] (3) Hydrogen decrepitation process: the furnace for hydrogen decrepitation with quenching alloy placed therein was vacuumed at room temperature, and then hydrogen gas with 99.9% purity was passed into the furnace for hydrogen decrepitation to maintain the hydrogen pressure at 0.15 MPa; after sufficient hydrogen absorption, it was sufficiently dehydrogenated by raising temperature while vacuuming; then it was cooled and the powder after hydrogen decrepitation was taken out.

[0155] (4) Micro-pulverization process: the powder after hydrogen decrepitation was pulverized by jet mill for 3 hours in nitrogen atmosphere with oxidizing gas content of 150 ppm or less and under the condition of the pressure of 0.38 MPa in the pulverization chamber, and fine powder was obtained. The oxidizing gas refers to oxygen or moisture.

[0156] (5) Zinc stearate was added to the powder after jet mill pulverization, and the addition amount of zinc stearate was 0.12% by weight of the mixed powder, and then it was mixed thoroughly by using a V-mixer.

[0157] (6) Magnetic field forming process: a rectangular oriented magnetic field forming machine was used to conduct primary forming of the above-mentioned powder with zinc stearate into a cube with sides of 25 mm at one time in an orientation magnetic field of 1.6 T and a forming pressure of 0.35 ton/cm.sup.2; after the primary forming, it was demagnetized in a magnetic field of 0.2 T. In order to prevent the formed body after the primary forming from air contact, it was sealed, and then secondary forming was carried out at a pressure of 1.3 ton/cm.sup.2 using a secondary forming machine (isostatic forming machine).

[0158] (7) Sintering process: each formed body was moved into a sintering furnace for sintering, and the sintering was maintained under a vacuum of 5×10.sup.-3 Pa and at a temperature of 300° C. and 600° C. for 1 hour, respectively; then, sintered at a temperature of 1040° C. for 2 hours; and then Ar gas was passed in to make the air pressure reach 0.1 MPa, and cooled to room temperature.

[0159] (8) Grain boundary diffusion treatment process: the sintered body of each group was processed into a magnet with a diameter of 20 mm and a thickness of 5 mm, and the thickness direction is the magnetic field orientation direction, after the surface was cleaned, the raw materials formulated with TbF.sub.3 or DyF.sub.3 were used respectively to coat on the magnet through a full spray, and the coated magnet was dried, and diffusion heat treatment was carried out at a temperature of 850° C. for 24 hours in a high-purity Ar gas atmosphere. Cooled to room temperature.

[0160] TbF.sub.3 was sprayed in examples 2, 3 and 6, and DyF.sub.3 was sprayed in the remaining examples and comparative examples.

[0161] (9) Heat treatment process: the sintered body was heat treated in high purity Ar gas at a temperature of 500° C. for 3 hours and then cooled to room temperature and taken out.

Effectiveness Example

[0162] The magnetic properties and compositions of the R-T-B-based sintered magnet prepared in Examples 1-11 and Comparative Examples 1-10 were measured, and the microscopic structure of the magnets was observed using FE-EPMA.

[0163] (1) Composition measurement: compositions were measured with high frequency inductively coupled plasma emission spectrometer (ICP-OES). Table 2 below shows the composition results.

TABLE-US-00004 NO. wt% R Nd PrNd Tb Dy X Al Cu Ga Co B Ti Zr Nb Fe Example 1 30.9 30.2 / / 0.7 1.27 0.6 0.42 0.25 1.0 0.96 0.4 / / 65.47 Example 2 30.5 29.9 / 0.5 0.1 0.85 0.3 0.35 0.2 1.0 0.95 0.3 / / 66.4 Example 3 31.0 30.3 / 0.5 0.2 1.0 0.4 0.4 0.2 0.8 0.97 0.45 / / 65.78 Example 4 31.5 30.0 / / 1.5 1.4 0.6 0.45 0.35 1.2 0.98 0.5 / / 64.42 Example 5 32.0 30.8 / / 1.2 1.8 0.8 0.5 0.5 1.5 0.99 0.55 / / 63.16 Example 6 30.9 / 30.2 0.5 0.2 1.37 0.7 0.42 0.25 2.0 0.97 0.6 / / 64.16 Example 7 30.9 30.2 / / 0.7 1.27 0.6 0.42 0.25 1.0 0.96 0.2 0.3 / 65.37 Example 8 30.5 29.9 / / 0.6 0.85 0.3 0.35 0.2 1.0 0.95 / 0.4 / 66.3 Example 9 30.5 29.9 / / 0.6 0.85 0.3 0.35 0.2 1.0 0.95 / 0.6 / 66.1 Example 10 31.0 30.2 / / 0.8 1.0 0.4 0.4 0.2 0.8 0.97 / / 0.35 65.88 Example 11 31.0 30.2 / / 0.8 1.0 0.4 0.4 0.2 0.8 0.97 / / 0.55 65.68 Comparative Example 1 30.5 29.9 / / 0.6 0.85 0.3 0.35 0.2 1.0 0.95 0 / / 66.7 Comparative Example 2 30.5 29.9 / / 0.6 0.85 0.3 0.35 0.2 1.0 0.95 0.7 / / 66.0 Comparative Example 3 31.5 30.5 / / 1.0 1.1 0.6 0.25 0.25 1.2 0.98 0.4 / / 64.82 Comparative Example 4 31.5 30.5 / / 1.0 0.7 0.2 0.35 0.15 1.2 0.98 0.4 / / 65.22 Comparative Example 5 31.5 30.5 / / 1.0 1.45 0.6 0.6 0.25 1.2 0.98 0.4 / / 64.47 Comparative Example 6 31.5 30.5 / / 1.0 0.95 0.5 0.2 0.25 1.2 0.98 0.4 / / 64.97 Comparative Example 7 30.9 30.2 / / 0.7 1.27 0.6 0.42 0.25 1.0 0.94 0.4 / / 65.49 Comparative Example 8 30.9 30.2 / / 0.7 1.27 0.6 0.42 0.25 1.0 1.02 0.4 / / 65.41 Comparative Example 9 30.0 29.0 / / 1.0 1.25 0.6 0.4 0.25 1.2 0.98 0.5 / / 66.07 Comparative Example 10 32.5 31.5 / / 1.0 1.25 0.6 0.4 0.25 1.2 0.98 0.5 / / 63.57

[0164] (2) Magnetic properties evaluation: the magnetic properties were examined using the NIM-10000H type BH bulk rare earth permanent magnet nondestructive measurement system in National Institute of Metrology, China. The following Table 3 indicates the magnetic property testing results.

TABLE-US-00005 NO. Br (kGs) Hcj (kOe) SQ Bhmax (Mgoe) Example 1 13.33 25.2 99.1 43.1 Example 2 13.40 27.2 99.2 43.3 Example 3 13.26 27.5 99.5 42.4 Example 4 13.11 26.3 99.4 41.9 Example 5 13.09 26.0 99.3 41.7 Example 6 13.38 27.8 99.8 41.6 Example 7 13.28 25.5 99.5 41.2 Example 8 13.3 25.8 99.6 42.9 Example 9 13.31 25.3 99.4 43.1 Example 10 13.27 25.9 99.2 42.7 Example 11 13.24 25.2 99.1 42.5 Comparative Example 1 13.33 24.7 91.5 41.8 Comparative Example 2 13.28 23.3 99.1 42.8 Comparative Example 3 13.3 22.8 99.0 42.9 Comparative Example 4 13.53 22.9 99.2 44.5 Comparative Example 5 13.13 22.6 99.3 41.8 Comparative Example 6 13.34 22.8 99.5 43.2 Comparative Example 7 13.03 22.4 96.6 40.2 Comparative Example 8 13.44 23.0 99.8 43.8 Comparative Example 9 13.46 22.3 97.8 43.5 Comparative Example 10 12.98 23.8 99.4 40.6

[0165] Table 3 shows that:

[0166] i. The R-T-B-based permanent magnet materials of the present invention have excellent performance with Br ≥ 13.09 kGs and Hcj ≥ 25.2 kOe (Example 1-1);

[0167] ii. Based on the formula of the present invention, as the amount of raw materials M, X, Cu, R and B is changed, the performance of the R-T-B-based permanent magnet materials decreases significantly and can not achieve the performance of the present invention (comparative example 1-10).

[0168] (3) FE-EPMA inspection: the perpendicularly oriented surface of the sintered magnet material was polished and inspected using a field emission electron probe micro-analyzer (FE-EPMA) (Japan Electronics Corporation (JEOL), 8530F). The distribution of R, Fe, Co, Ti, Nb, Zr, B, Al, Cu,Ga and other elements in the magnet material was first determined by FE-EPMA surface scanning, and then the content of R, Fe, Co, Al, Cu, Ga, Ti, Nb, Zr and other elements in the R-M-X-T phase was determined by FE-EPMA single-point quantitative analysis with the test conditions of acceleration voltage 15kv and probe beam current 50nA.

[0169] The FE-EPMA inspection was performed on the sintered magnet material prepared in Example 1, and the results are shown in Table 4 below.

[0170] Table 4 shows the results of FE-EPMA single-point quantitative analysis of the R-M-X-T-rich phase in FIG. 1. From Table 4, it can be seen that, in the R-M-X-T-rich phase, R is about 19.98 at%, M is about 3.03 at%, X is about 5.46 at%, and T is about 71.54 at%.

TABLE-US-00006 R T X M phase component Nd Dy Fe Co Ga Cu Al Ti 19.07 0.91 71.41 0.13 4.21 1.17 0.08 3.03 R.sub.19.98M.sub.3..sub.03X.sub.5.sub...sub.46 T.sub.71.54